Rotary expansion engine of the type having planetating rotor

ABSTRACT

The rotary expansion engine of the type having a planetary rotor has, in the rotor, passageway means to receive pressurized fluid from a source thereof and port means for passing the pressurized fluid into the working chambers, the timing and the control of flow of fluid through such port means being regulated by the rotor rotation and port location relative to the engine housing.

Unite States Patent [191 [111 3,881,847 Chen May 6, 1975 [54] ROTARY EXPANSION ENGINE OF THE 3,340,853 9/1967 Link 418/187 TYPE HAVING PLANETATING ROTOR immermafln at 1 eane [75] Inventor: Hsin S. Chen, Hasbrouck Heights,

Primary Examiner-John J. Vrablik [73] Assignee: Curtiss-Wright Corporation, Attorney, Agent, or Firm-Arthur Frederick; Victor D.

Wood-Ridge, N.J. Behn [22] Filed: Nov. 30, 1973 21 Appl. No.: 420,445 [57] ABSTRACT The rotary expansion engine of the type having a planetary rotor has, in the rotor, passageway means to re- Z 5 ff 3; ceive pressurized fluid from a source thereof and port d "4 l 3 c means for passing the pressurized fluid into the work- 1 le 0 earc 18 186-188 ing chambers, the timing and the control of flow of fluid through such port means being regulated by the [56] References c rotor rotation and port location relative to the engine UNITED STATES PATENTS housing 2,988,065 6/1961 Wankel et a1 4l8/6l A 3,180,323 4/1965 Paschke 418/183 8 Clam, 4 Drawmg F'gures PATENIEDHAY isms 3.881.847

SHEET 2!}? 3 ROTARY EXPANSION ENGINE OF THE TYPE IIAVING PLANETATING ROTOR This invention relates to rotary expansion engines of the type having a planetary rotor and, more particularly, to an improvement in such engines for effecting rotation of the rotor.

In rotary expansion engines of the various types exemplifled in the US. Pat. Nos. to Rasck, No. 1,655,738; Plato, 1,968,537; Kalkbrenner, 3,535,059; George, 3,628,899; and Pierce et al 3,744,940 and the British Pat. No. 989,588 to Linder, the flow of pressurized driving fluid into the working chambers is controlled by valves external to the engine cavity, the actuation of which valves is synchronized with the rotor rotation through the crankshaft and gear trains or pulleybelt systems. This necessity for external valves and mechanisms for timing their operation results in an expansion engine of relatively great complexity, bulkiness and cost. Therefore, heretofore expansion engines of the Wankel type have not been competitive with sliding vane type expander engines in spite of the greater capability and efficiency of the Wankel type engines.

It is therefore an object of this invention to provide an expansion engine of the type having a planetary rotor which engine does not require external intake port valves and timing drive mechanisms and is therefore relatively simple in construction and inexpensive to fabricate.

It is another object of the present invention to provide an expansion engine of the planetary rotor type which is relatively small in size relative to capacity.

SUMMARY Accordingly, this invention contemplates a rotary expansion engine of the type having a planetary rotor which itself functions to control the introduction of pressurized driving fluid into the working chambers of the engine at predetermined times and duration and thereby eliminates the need for external valves and timing mechanisms.

The rotary expansion engine of this invention comprises a housing in which, at least, one rotor is eccentrically supported for rotation, the housing and rotor defining a plurality of working chambers which, as the rotor rotates relative to the housing, expand and contract in volumetric size. The housing has opposite end walls spaced by a peripheral wall while the rotor consists of opposite side wall surfaces interconnected by a plurality of peripheral flank surfaces, one of each of the side wall surfaces lying adjacent an end wall of the housing. A seal means is disposed in the interstices between each of the housing end walls and the side wall surfaces of the rotor to prevent passage of fluid through such interstices. A first passageway means is provided in the rotor to communicate with a source of pressurized fluid to receive such fluid from the latter. A port means is also provided in said rotor which communicates with the first passageway means and at least one of the interstices between an end wall and the adjcant side wall surface of the rotor at a point radially inward of the seal means. A second passageway means is formed in the end wall surface adjacent the side wall surface having said port means, which second passageway means is constructed and arranged to by-pass pressurized fluid around said seal means and to intermittently communicate the port means with a fluid tight working chamber as the rotor rotates thereby delivering pressurized fluid to such working chamber at a time when the pressurized fluid is capable of exerting a torque force on the rotor and effecting rotation of the rotor as the pressurized fluid expands. An exhaust means is provided which communicates with the working chambers for passing spent pressurized fluid from the working chambers following expansion of the pressurized fluid.

In one embodiment of the invention the port means includes an annular groove while in another embodiment of the invention the port means includes a plurality of circumferentially spaced openings.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be more fully understood from the following detailed description thereof when considered in connection with the accompanying drawing wherein two embodiments of the invention are illustrated by way of example and in which:

FIG. I is a transverse cross-sectional view through an expansion engine according to one embodiment of this invention;

FIG. 2 is a view in cross-section taken substantially along line 22 of FIG. 1;

FIG. 3 is a schematic view showing how rotation of the rotor controls delivery of pressurized fluid to the working chambers; and

FIG. 4 is a view similar to FIG. 1 showing another embodiment of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Now referring to the drawings and more specifically to FIGS. I to 3, the reference number 10 generally designates an expansion engine according to this invention. For purposes of this description the expansion engine will be shown and described as a Wankel type having a three-sided rotor eccentrically rotating in a twolobed epitrochoidal shaped housing cavity such as disclosed in the US. Pat. to George, No. 3,628,899 and Pierce No. 3,535,059. While expansion engine 10 will be described as of the Wankel type having a generally triangular shaped rotor it is to be understood that the invention is not limited thereto. The rotor may have two or more than three sides or flank portions in a housing cavity having one or more than two lobes without departure from the scope and spirit of this invention. Also, without transcending the scope and spirit of this invention, the expansion engine may be of the type shown in the British Patents to Maillard No. 583,035 or Linder No. 989,588.

The expansion engine 10 as illustrated in FIGS. 1 to 3 comprises a housing 11 having two end walls 12 and 14 attached to an intermediate wall 16 to define a cavity within which a rotor 18 is supported for rotation on an eccentric portion 20 of a crankshaft 22. The intermediate wall 16 has an inner peripheral surface 24 of epitrochoidal configuration to form a housing cavity profile of two lobes. The rotor 18 comprises a generally triangular body having opposite side wall faces or surfaces 26 and 28 and three contiguous peripheral flank portions 30, the flank portions 30 meeting each other at an apex portion 32. The rotor 18 is so dimensioned that side wall surfaces 26 and 28 lie in close spaced relationship with the inner surfaces of end walls 12 and 14, respectively, and define with the housing three working chambers A, B, and C. The relative angular position of rotor 18 to the housing 11 is maintained by the conventional meshing internal gear 34 carried by the rotor and a fixed pinion gear 36 (see FIG. 2).

The working chambers are maintained out of communication with each other and substantially fluid tight by appropriate sealing means. The sealing means may, as shown, comprise an apex seal blade assembly 38 carried in each of the apex portions 32 of the rotor to engage the inner trochoidal surface 24 of housing 11. In addition, the sealing means includes a plurality of arcuate shaped side seal strips 40 which are carried in each of the side wall surfaces 26 and 28 to engage the adjacent end walls 12 and 14 of housing 11. Also, the sealing means may include an annular seal ring 42 carried in each of the side wall surfaces 26 and 28 to engage the adjacent end walls 12 and 14, this seal ring 42 being spaced radially inwardly from the side seal strips 40. To effect a seal at each of the junctures of apex seal blade assemblies 38 and side seal strips 40, a seal pin 44 is provided.

The expansion engine is rotated by the introduction of pressurized fluid, gas or liquid, into the working chambers A, B, and C at the proper time by passageway means in accordance with this invention. This passageway means includes chamber or cavity 46 in rotor 18. In the case of a rotor, such as disclosed in the US. Pat. to Hermes et al No. 3,655,302, constructed with radial ribs 48 and an annular central web 50 for interconnecting a hub portion 45 and flank portion 30, the cavity 46 is the space formed between ribs 48 and web 50. To communicate the spaces on opposite sides of web 50, web 50 is provided with a plurality of openings 52 therein. To conduct pressurized fluid from a suitable source thereof (not shown) into rotor cavity 46 a supply passageway is provided. This supply passageway may be in the form of a longitudinal bore 54 in the crankshaft 22, radially extending branch passages 56 and the space 47 between rotor hub 45 and end wall 12. Also, in accordance with this invention, rotor 18 is provided in side wall surfaces 26 and 28 with an annular groove 58 (see FIG. 1) which is brought into communication with cavity 46 by a plurality of circumferentially spaced holes 60. The groove 58 is dimensioned so as to be disposed between seal ring 42 and side seal strips 40. Thus, pressurized fluid is conducted from a source thereof (not shown) into the interstices between end walls 12 and 14 and side wall surfaces 26 and 28, respectively, via supply passageway 54, branch passages 56, space 47, rotor cavity 46, holes 60 and grooves 58. The side seal strips 40 and apex seal pins 44 prevent the pressurized fluid conducted into the interstices from flowing into working chambers A, B and C except periodically as hereinafter explained.

As best illustrated in FIG. 3, each groove 58 is intermittently brought into communication with each of two pairs of radially extending grooves 62. Each pair of grooves 62 is located in housing walls 12 and 14 and are coextensive with the minor axis of housing 11. Each of the grooves of each pair of grooves is dimensioned in length to extend from a point where grooves 58 are brought closest to inner housing surface 24 by the eccentric rotation of rotor 18 within housing 11 and to a point adjacent inner housing surface 24 (see FIG. 2). This position of grooves 58 is shown in full lines in FIG. 3 and is a location where rotor 18 is substantially at top center. As can best be seen in FIG. 2, grooves 62 serve to bypass pressurized fluid around side seal strips 40 so that pressurized fluid is passed into working chamber A. As shown by the dot-dash lines, this flow of pressurized fluid is cut off to working chamber A when rotor 18 rotates so as to carry groove 58 out of communication with groove 62. The flow of pressurized fluid is not again allowed to flow to working chamber A until the rotor moves a short distance from the position before top center shown by the dotted lines. Thus, in accordance with this invention rotor 18 relative to the size and location of the port means (holes and grooves 58) serves as a valve to control flow of pressurized fluid at the proper time and for proper duration to working chambers A, B and C to thereby effect rotation of rotor 18 in a predetermined manner. With two grooves 62 in each set as shown, the rotor is subjected to two power impulses for each revolution of rotor 18.

The spent pressurized fluid, after it has undergone expansion and exertion of a torque force on rotor 18, is discharged from the working chambers by exhaust ports 64. Since the rotor is subject to two power impulses, two exhaust ports 64 are provided in end wall 12 of housing 11. As is conventional and well known in the art, exhaust ports 64 are so sized and positioned that the sweep of side seal strips 40 opens and closes the exhaust ports at the proper time.

The expansion engine 10 has a starter system (not shown) which may be a suitable motor means connected to rotate the crankshaft or a pressurized fluid system such as disclosed in British Pat. No. 8949 to Phippen for effecting rotation of rotor 18. Of course, once self-sustained rotor rotation is achieved the starter system can be shut off.

In operation of expansion engine 10 assuming operation of a starter system (not shown) to effect rotation in a clockwise direction as viewed in FIGS. 1 and 3, pressurized driving fluid is released to bore 54 from where it flows by way of branch passages 54 passed hub portion 45 into the cavity 46 of rotor 18. If at this time the rotor is in a position where grooves 58 are out of communication with grooves 62, such as the two positions shown by the dot-dash and the dotted lines, pressurized fluid is not delivered to working chamber A until the starter system rotates rotor 18 to a position where grooves 58 are in communication with grooves 62. When this communication is effected, pressurized fluid is delivered to working chamber A. The drive or momentum of the rotor carries it to a position where the pressurized fluid, as it expands, exerts a torque force on the flank portions 30 of rotor 18 in a clockwise direction. After the expansion of the pressurized fluid (power impulse) one of the exhaust ports 64 is brought into communication with working chamber A to pass the spent gas from the working chamber, further rotation of rotor 18 functioning to displace the remaining spent pressurized fluid as the rotor moves into a position for another power impulse by pressurized fluid conducted into the working chamber by the other set of grooves 62. After sustained operation of expansion engine 10 is assured, the starter system is shut-off.

In FIG. 4 is shown another embodiment of the present invention which only differs from that shown in FIGS. 1 to 3 in that in place of each of the grooves 58 three elongated openings 66 are provided for communicating and passing pressurized fluid to grooves 62. Parts of this embodiment shown in FIG. 3 corresponding to like parts of the expansion engine shown in FIGS.

1 to 3, have been designated by the same reference numbers.

It is believed now readily apparent that the present invention provides an expansion engine having a planetary rotor which is of relatively simple construction and inexpensive. It is an expansion engine in which pressurized fluid intake into the working chambers is controlled directly by rotor rotation and thus eliminates the need for external valves and timing mechanisms.

Although two embodiments of the invention have been illustrated and described in detail, it is to be expressly understood that the invention is not limited thereto. Various changes can be made in the arrangement of parts without departing from the spirit and scope of the invention as the same will now be understood by those skilled in the art.

What is claimed is:

1. A rotary expansion engine comprising:

a. a housing having opposite end walls spaced apart by a trochoidal peripheral wall and defining therebetween a multi-lobe trochoidal shaped cavity;

b. said lobes meeting each other at lobe junctures;

c. a rotor having opposite side wall surfaces interconnected by a plurality of peripheral flank surfaces;

d. the rotor supported for eccentric rotation within said cavity and disposed therein with one of each of the side wall surfaces lying adjacent an end wall of the housing;

e. seal means disposed in the interstices between each of the end walls and adjacent side wall surfaces of the rotor;

f. the rotor and housing defining therebetween a plurality of working chambers which successively expand and contract as the rotor eccentrically rotates within the housing cavity;

g. a first passageway means in said rotor communicating with a source of pressurized fluid to receive the latter;

h. port means in said rotor communicating with said first passageway means and the interstices between the end wall of the housing and the adjacent side wall surface of the rotor;

. second passageway means in at least one of the end wall surfaces located adjacent each of the lobe junctures for bypassing pressurized fluid around said seal means and located and sized so as to intermittently communicate the port means with a fluid tight working chamber as the rotor rotates thereby delivering pressurized fluid to such working chamber for effecting expansion of the pressurized fluid and rotation of the rotor; and

. exhaust means communicating with the working chambers for passing spent pressurized fluid from the working chambers following expansion of the pressurized fluid.

2. The apparatus of claim 1 wherein said rotor is supported by a crankshaft and said first passageway means includes conduit means in the crankshaft which conduit means communicates with the source of pressurized fluid.

3. The apparatus of claim 1 wherein said port means is a plurality of circumferentially spaced openings in each of the side wall surfaces.

4. The apparatus of claim 1 wherein said second passageway means is a groove in each end wall surface and extending to a point of intersection with the path of movement of said port means.

5. The apparatus of claim 1 wherein said port means includes an annular groove in each of said opposite side wall surfaces of the rotor.

6. The apparatus of claim 5 wherein said second passageway means is a groove in each end wall surface extending substantially radially relative to the axis of planetation of the rotor.

7. The apparatus of claim 1 wherein said seal means includes first seal means and radially inwardly spaced second seal means and wherein said port means is located between said first and second seal means.

8. The apparatus of claim 7 wherein said port means includes an annular groove in each of said opposite side wall surfaces of the rotor. 

1. A rotary expansion engine comprising: a. a housing having opposite end walls spaced apart by a trochoidal peripheral wall and defining therebetween a multilobe trochoidal shaped cavity; b. said lobes meeting each other at lobe junctures; c. a rotor having opposite side wall surfaces interconnected by a plurality of peripheral flank surfaces; d. the rotor supported for eccentric rotation within said cavity and disposed tHerein with one of each of the side wall surfaces lying adjacent an end wall of the housing; e. seal means disposed in the interstices between each of the end walls and adjacent side wall surfaces of the rotor; f. the rotor and housing defining therebetween a plurality of working chambers which successively expand and contract as the rotor eccentrically rotates within the housing cavity; g. a first passageway means in said rotor communicating with a source of pressurized fluid to receive the latter; h. port means in said rotor communicating with said first passageway means and the interstices between the end wall of the housing and the adjacent side wall surface of the rotor; i. second passageway means in at least one of the end wall surfaces located adjacent each of the lobe junctures for bypassing pressurized fluid around said seal means and located and sized so as to intermittently communicate the port means with a fluid tight working chamber as the rotor rotates thereby delivering pressurized fluid to such working chamber for effecting expansion of the pressurized fluid and rotation of the rotor; and j. exhaust means communicating with the working chambers for passing spent pressurized fluid from the working chambers following expansion of the pressurized fluid.
 2. The apparatus of claim 1 wherein said rotor is supported by a crankshaft and said first passageway means includes conduit means in the crankshaft which conduit means communicates with the source of pressurized fluid.
 3. The apparatus of claim 1 wherein said port means is a plurality of circumferentially spaced openings in each of the side wall surfaces.
 4. The apparatus of claim 1 wherein said second passageway means is a groove in each end wall surface and extending to a point of intersection with the path of movement of said port means.
 5. The apparatus of claim 1 wherein said port means includes an annular groove in each of said opposite side wall surfaces of the rotor.
 6. The apparatus of claim 5 wherein said second passageway means is a groove in each end wall surface extending substantially radially relative to the axis of planetation of the rotor.
 7. The apparatus of claim 1 wherein said seal means includes first seal means and radially inwardly spaced second seal means and wherein said port means is located between said first and second seal means.
 8. The apparatus of claim 7 wherein said port means includes an annular groove in each of said opposite side wall surfaces of the rotor. 